An alpheid shrimp digs and maintains a deep burrow. While underground, the shrimp is safe. Above ground, it is vulnerable to predators. A goby fish lives in the burrow with the shrimp. The goby fish sits at the entrance, keeping watch for predators, and signals the shrimp with a flick of its tail when it is safe to come out. Or, if a predator swims by, the goby darts into the burrow and the shrimp retreats further inside. These two animals are completely dependent on each other—the goby benefits by getting a burrow to live in and the shrimp knows when predators are near.

ase of convenience, since the beneficiary by having a burrow and the shrimp benefits from knowing that there are predators nearby.

Explanation:

This exercise asks to study the dependence between two animals, the shrimp and the puffer fish.

Two types of dependency are defined:

* Complete. What is when one animal lives off the other

* Convenience if one animal does not live on the other

In this case, both the shrimp and the predator do not live on each other, since they feed independently.

So it is a case of convenience, since the beneficiary by having a burrow and the shrimp benefits from knowing that there are predators nearby.

The correct answer is: the balloon benefits by getting a burrow to live in and the shrimp knows when predators are nearby.

a. are